Elbow arthroplasty apparatus, system, and method

ABSTRACT

The present disclosure generally relates to an elbow arthoplasty prosthesis that includes an ulnar component, a humeral component, one or more articulation liners, and a retention trap. The ulnar component includes a spherical bearing head that can be inserted into the humeral component in a number of orientations. The articulation liners and the retention trap are operatively engaged to the humeral component to retain the ulnar component within a humeral socket. The present disclosure also relates to methods of assembling and implanting the prosthetic device.

RELATED APPLICATIONS

The application claims priority to U.S. Provisional Application No.62/111,963, entitled “Elbow Arthroplasty Apparatus, System, And Method,”filed on Feb. 4, 2015 which is incorporated herein by reference in itsentirety, including any appendices.

TECHNICAL FIELD

Aspects of the present disclosure relate to joint apparatuses and inparticular apparatus, systems, and methods for elbow arthroplasty.

BACKGROUND

Joint arthroplasty is a mechanism commonly used for relieving pain andrestoring function to patients suffering from arthritis and otherdestructive joint problems, in joints such as the elbow. Advancements inimplant designs and surgical techniques have made elbow arthroplasty asatisfactory treatment for arthritic disorders.

SUMMARY

The present disclosure generally relates to an elbow arthoplastyapparatus and system that may be used in elbow replacement. In variousembodiment, that disclosed system includes an elbow prosthesis and/orimplant device and related instruments and components that may be usedto implant the elbow prosthesis.

In one embodiment, an elbow arthoplasty apparatus an ulnar component, ahumeral component, at least one articulation liner, and a retentiontrap. The ulnar component further includes a spherical bearing headhaving one or more projection ears extending away from the bearing headalong a central transverse axis of the bearing head. The bearing head isoperatively engaged to an ulnar stem extending away from the bearinghead in a direction generally perpendicular to the transverse axis.

The humeral component includes a yoke, and a pair of opposing yextending from the yoke. An interior surface, of each yoke branch isconcave. An exterior surface of each yoke branch is convex. The yokebranches define a spherical socket to retain the bearing head whendisposed in the socket. The humeral component also includes a stemextending from the yoke opposite the pair opposing yoke branaches.

The at least one articulation liner is operatively engaged to theinterior surface of at least one of the pair of yoke branches. The atleast one articulation liner is also disposed within the sphericalsocket between the at least one yolk branch and the spherical bearinghead. The retention trap is operatively engaged to the pair of opposingyoke branches, the at least one articulation liner, the bearing head andthe one or more projection ear.

In one embodiment, a method of implanting the elbow arthoplastyapparatus includes obtaining the elbow prosthesis. The elbow prosthesisincludes an ulnar component including a bearing end and an ulnar stem.The ulnar stem is coupled to the bearing end and extends away from thebearing end. The elbow prosthesis also includes a humeral componentincluding a holder end and a humeral stem. The humeral stem extends awayfrom the holder end. The elbow prosthesis further includes at least onebearing liner coupled to the holder end. The bearing end is configuredto be coupled within the holder end to articulate against the at leastone bearing liner.

The method includes making an incision in the patient, determining theproper size for the ulnar component and the humeral component, andpreparing an ulna and a humerus of the patient. The method also includessecuring the humeral component into the humerus of the patient,attaching the ulnar component to the humeral component, securing theulnar component into the ulna of the patient, and closing the incisionin the patient.

In one aspect, a method of implanting an elbow arthoplasty apparatus mayalso include inserting the bearing end of the ulnar component into theholder end of the humeral component adjacent to the at least one bearingliner. A retention trap is inserted into the holder end. The method mayalso include securing the at least one bearing liner to an inner surfaceof the holder end by rotating the at least one bearing within thehumeral component to engage a locking flange of the bearing liner withthe a locking shoulder of the humeral component. This may beaccomplished by rotating the retention trap and the at least one bearingliner relative to the humeral component to lock the retention trap andthe at least one bearing liner to the humeral component.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features, and advantages of the presentdisclosure set forth herein will be apparent from the followingdescription of particular embodiments of those inventive concepts, asillustrated in the accompanying drawings. Also, in the drawings the likereference characters refer to the same parts throughout the differentviews. The drawings depict only typical embodiments of the presentdisclosure and, therefore, are not to be considered limiting in scope.

FIG. 1 is an isometric view of an elbow implant device in a fullyassembled configuration.

FIG. 2 is a left side elevation of the elbow implant device of FIG. 1.

FIG. 3 is a right side elevation of the elbow implant device of FIG. 1.

FIG. 4 is a front orthographic view of the elbow implant device of FIG.1.

FIG. 5 is a rear orthographic view of the elbow implant device of FIG.1.

FIG. 6 is a top perspective view of the elbow implant device of FIG. 1.

FIG. 7 is a bottom perspective view of the elbow implant device of FIG.1 without a retention trap.

FIG. 8 is an exploded view of the elbow implant device of FIG. 1 in anunassembled configuration.

FIG. 9 is an isometric view of the humeral component of the elbowimplant device of FIG. 8.

FIG. 10 is a bottom perspective view of the humeral component of theelbow implant device of FIG. 9.

FIG. 11 is a left side elevation of the humeral component of the elbowimplant device of FIG. 9.

FIG. 12 is an isometric half-section view of the humeral component ofthe elbow implant device of FIG. 9.

FIG. 13 is an isometric view of a bearing head, neck, and stemreceptacle of the ulnar component of the elbow implant device of FIG. 9.

FIG. 14 is a rear perspective view of the bearing head, neck, and stemreceptacle of the ulnar component of the elbow implant device of FIG.13.

FIG. 15 is a right side elevation view of the bearing head, neck, andstem receptacle of the ulnar component of the elbow implant device ofFIG. 13.

FIG. 16 is a bottom orthographic view of the bearing head, neck, andstem receptacle of the ulnar component of the elbow implant device ofFIG. 13.

FIG. 17 is an isometric view of a stem of the ulnar component of theelbow implant device of FIG. 9.

FIG. 18 is an isometric view of an articulation liner of the elbowimplant device of FIG. 9.

FIG. 19 is a front elevation view of the articulation liner of the elbowimplant device of FIG. 18.

FIG. 20 is a top orthographic view of the articulation liner of theelbow implant device of FIG. 18.

FIG. 21 is a top isometric view of a retention trap of the elbow implantdevice of FIG. 9.

FIG. 22 is a bottom isometric view of the retention trap of the elbowimplant device of FIG. 21.

FIG. 23 is a front elevation view of the retention trap of the elbowimplant device of FIG. 21.

FIG. 24 is a side elevation view of the retention trap of the elbowimplant device of FIG. 21.

FIG. 25 is a bottom orthographic view of the retention trap of the elbowimplant device of FIG. 21.

FIG. 26 is an isometric view of a pair of articulation liners engaged toa retention trap of the elbow implant device of FIG. 9.

FIG. 27 is a rear perspective view of a pair of articulation linersengaged to a retention trap of the elbow implant device of FIG. 26.

FIG. 28 is an isometric view of an ulnar component operatively engagedto a pair of articulation liners and a retention trap of the elbowimplant device of FIG. 9.

FIG. 29 is a flow chart of a method to implant the elbow implant deviceof FIG. 1, according to one embodiment.

FIG. 30 is an illustration of an existing elbow arthoplasty device thatmust be assembled in a single configuration.

FIG. 31 is an illustration of one embodiment of the present elbowarthoplasty device that may be assembled in a number of configurations.

FIG. 32 is a rear isometric view of a step of a method to implant theelbow implant device according to one embodiment.

FIG. 33 is a rear isometric view of a step of a method to implant theelbow implant device according to one embodiment.

FIG. 34 is a rear isometric view of a step of a method to implant theelbow implant device according to one embodiment.

FIG. 35 is a front isometric view of the step of a method to implant theelbow implant device shown in FIG. 34, according to one embodiment.

FIG. 36 is a rear isometric view of one step of a method to implant theelbow implant device according to one embodiment.

DETAILED DESCRIPTION

Aspects of the present disclosure involve an elbow arthoplasty apparatusand system that may be used in elbow replacement. In one aspect, thedisclosed system includes an elbow prosthesis and/or implant device andrelated instruments and components that may be used to implant the elbowprosthesis. In another aspect, the disclosed prosthetic device is atotal elbow arthroplasty device designed to restore range of motion tothe elbow while replacing the native bony and articulating anatomy ofthe ulnohumeral interface.

The elbow arthoplasty apparatus disclosed herein includes variousembodiments of an implantable prosthetic device that generally comprisesa humeral component, an ulnar component, one or more articulationbearing inserts or liners, and a retention trap, all assembled to form ageneral a ball and socket type configuration. The humeral component andulnar component are articulable relative to one another, while thevarious liners and retention devices associated with the ball- andsocket connection to permit easier assembly or replacement of theprosthesis. In various embodiments, the prosthetic device 10 is providedin a variety of sizes and may be configured for implantation into avariety of patients such as pediatric patients or adult patients.

Referring to FIGS. 1-8, the elbow prosthesis or prosthetic device 10comprises the humeral component 100 and the ulnar component 200. Theelbow prosthesis 10 further includes one or more bearing liner, referredto herein as an articulation liner 300 and a retention trap 400, asshown in FIG. 8.

The Humeral Component

In various embodiments, the humeral component 100 includes an elongatedhumeral stem 102, an elongated humeral flange 104, and a holder end,referred to herein as humeral socket 106. In one aspect, the humeralcomponent 100 is composed of a bio-compatible metal or metal alloy isdesigned for cemented fixation within the humeral canal of a patient. Byway of example, the humeral component 100 may be composed of Grade 5 orGrade 23 titanium, such as that having the formula Ti-6AI-4V. Othersuitable metals and metal alloys including other titanium alloys mayalso be used. Additionally, various other biocompatible materialsincluding other metals, and polymers, or combinations thereof may beused for the humeral component 100, as well as any other portion of theprosthetic device 10.

The humeral stem 102 includes a proximal end 108 that extends proximallyfrom the humeral socket 106 and a distal end 110 that transitions intothe humeral socket 106. The proximal end 108 of the humeral stem 102 hasa generally rectangular cross-section and is dimensioned forimplantation in the humerus. In one aspect, the rectangularcross-section of the humeral stem 102 provides rotational stability.Similarly, the humeral flange 106 contacts the anterior surface of thedistal humerus after implantation. The rectangular cross-section of thehumeral flange 106 thus maximizes the surface contact area with theanterior surface of the humerus. The width of the proximal end 108 ofthe humeral stem 102 increases along the length of the stem to a widthof as it transitions into the distal end 110 that is proximal to thehumeral socket 106, as shown in FIG. 5. The dimensions and ratio of thetaper along the length of the stem may depend upon the size of thedevice implanted.

The humeral flange 104 extends proximally from an anterior surface 112of a humeral socket yoke 114 and extends towards the proximal end 108 ofthe humeral stem 102. The humeral flange 104 extends in a planesubstantially parallel to the humeral stem 102. As shown in FIGS. 1-3,8, 9, 11, and 12, the humeral flange 104 includes a flange extension 116and a flange base 118. The flange base 118 has the generally the samewidth as the flange extension 116. As shown in FIG. 3, the flange base118 as a general arced configuration and tapers from a first thicknesswhere it contacts the yoke 114 to a thickness that is substantiallyequal to the thickness of the humeral flange 104. In one aspect, theanterior humeral flange 104 provides support and rotational stabilityagainst torsional and posterior directed loads on the prosthesis 10.

As generally shown in FIGS. 1 and 8-10, the humeral socket 106 defines acavity 120 which holds and retains the articulation liners 300, theulnar component 200, and the retention trap 400 once the prosthesis 10is fully assembled. In various embodiments, the humeral socket yoke 114forks into two substantially parallel yoke branches 122. The humeralsocket 106 receives and retains a ulnar bearing end, also referred toherein as bearing head 204 in a manner that permits articulation of theulnar component 200 relative to the humeral component 100.

Referring now to FIGS. 8-10 and 12, in one embodiment, the interiorsurface 126 of each yoke branch 122 is generally concave and definehemispherical recess 126, respectively, as shown in FIG. 12, thattogether define the cavity 120. Similarly, the exterior surfaces of eachyoke branch defines a generally convex hemispherical surface 128. Eachof the yoke branches 122 further includes a bearing bore 130, co-axiallyaligned with the pole of each hemispherical recess 126 and extendingmedially or laterally from the interior surface 126 to the exteriorsurface 128 of the branch.

In one embodiment, as shown in FIGS. 1, 6, 7, and 10, the exteriorsurface each of the yoke branches 122 are further defined by cutouts 132that further a ridge 134 in a plane substantially parallel to thehumeral stem 102. Each ridge 134 includes an anterior sidewall 136 andposterior sidewall 138. In this embodiment, the anterior sidewall 136,the posterior sidewall 138, or both further optionally include one ormore suture bores 140 extending from the exterior of the respectivesidewall 136 and/or 138 to the interior surface of the bearing bore 130.The suture bores 140 allow for the repair of soft tissue adjacent to thehumeral component 100, the attachment of the prosthesis 10 to adjacentsoft tissue, the attachment of the prosthesis 10 to the humeralcondyles, or combinations thereof.

As shown in FIGS. 9 and 12, the interior edges 142 of the yoke branches122 define a slot 144 for receiving the ulnar component 200, thearticulation liners 300, and the retention trap 400. The slot 144further comprises a number of trap shoulders 146 to engage the retentiontrap 400, as well as a lock shoulder 148 to mechanically engage a flange320 on the articulation liners 300, as shown in FIG. 7. The slot 144further includes a narrowed or throttled region 149 that is formed byopposing tapered portions 147 of the interior edge 142 of the yokebranches 122, as shown in FIGS. 7, 10, and 12.

The Ulnar Component

In various embodiments, as shown in FIGS. 1-3, and 8, the ulnarcomponent 200 is designed and configured for cemented fixation withinthe ulnar canal of a patient. The ulnar component 200 includes an ulnarstem 202 coupled to the ulnar bearing head 204 via an ulnar neck 206. Inone aspect, the ulnar neck 206 extends at an acute angle “a” distallyfrom the ulnar bearing head 204 in an anterior direction, as shown inFIG. 15. The ulnar neck 206 further includes a collar 208 from which astem receptacle 210 extends in an anterior direction. In one embodiment,the stem receptacle 210 has a generally cylindrical or frustoconicalgeometry. Alternatively, the stem receptacle may defined by other shapesor cross-sectional geometries. As shown in FIGS. 8 and 17, a proximalend 212 of the ulnar stem 202 may include mating features 214 such asprojections, recesses, or both for securely mating with complimentarystructures (not shown) within the stem receptacle 210. Alternately, theulnar stem 202 may be engaged to the stem receptacle 210 through anysuitable arrangement, including but not limited to a friction-fit or athreaded arrangement. In one aspect, the stem receptacle 210 defines alumen 232 extending through the entire longitudinal length of thereceptacle. As such, the receptacle lumen 232 may receive a toolopposite the stem 202 for using during implantation.

In yet another embodiment, the ulnar stem 202 and ulnar neck 206 may befabricated in such a manner as to provide a unitary single-construct. Inone aspect, as shown in FIGS. 14 and 16, the stem receptacle 210, andthus the ulnar stem 202 are angled laterally away from a longitudinalaxis 216 of the ulnar bearing head 204, as generally indicated by 218.In various embodiment, the angle of deflection 218 is in a range betweenabout 3.5 to 6.5 degrees. In one particular, embodiment, the angle ofdeflection 218 was approximately 5 degrees. In various aspects, theangle of deflection 218 replicates the natural carrying angle of theforearm. As such, the angle of deflection various in differingembodiments to account for anatomic differences and fit across male andfemale patients as well as differences between adult and pediatricpatients.

The ulnar stem 202 is dimensioned for implantation within at least aportion of the proximal region of a patient's ulna. In various aspects,the ulnar stem 202 may be composed of one or more metallic or metallicalloy components. By way of example, the ulnar stem 202 may be composedof a single metal such as, but not limited to as cobalt-chrome (CoCr)alloy. In another aspect, the ulnar component 200 may be composed of oneor more metal alloys. For example, the ulnar stem 202 may include a CoCrproximal portion, while the bearing head 204 and neck 206 are composedof titanium or a titanium alloy. Alternately, the entire ulnar component200 may be composed of the same material.

The ulnar bearing head 204 is a spherical structure engaged to the ulnarneck 206. In various embodiments, the ulnar bearing head 204 may beintegral with the ulnar neck 206. In other embodiments, the ulnarbearing head 204 may be formed separately from one or more otherportions of the ulnar component 200.

The ulnar bearing head 204 includes opposing ulnar bearing projectionsor ears 220. The ulnar bearing ears 220 extend away from the medial andlateral sides of the ulnar bearing surface 222 and are coaxial with acentral transverse axis 224, as shown in FIGS. 14 and 16. In one aspect,the ulnar bearing ears 220 provide a transverse axis of rotation orarticulation for the ulnar component 200, generally indicated as 224 inFIG. 13, when disposed within the humeral component 100.

The Articulation Bearing Liners

The elbow prosthesis 10 also includes one or more of the resilientarticulation bearing inserts or liners 300, as shown in FIGS. 9, 18-20,and 26-28. In one embodiment, the elbow prosthesis 10 includes twoarticulation liners 300 that appear as mirror-images of each other andmay be identified as a lateral articulation liner and a medialarticulation liner. The liners 300 are composed of a polymer, includingbut not limited to polyethylene. In one aspect, the liners 300 aid thearticulation of the ulnar component 200 by preventing metal-on-metalcontact between the ulnar component and the humeral component 100. Inanother aspect, each of the liners 300 includes an exterior humeralinterface surface 302 that remains fixed in a static orientationrelative to the humeral component 100 following insertion and locking ofthe retention trap 400, as explained more fully below.

The exterior humeral interface surface 302 of the liners 300 has agenerally hemispherical configuration similar to the interior surface124 of each respective yoke branch 122. As such, the humeral interfacesurface 302 contacts the interior surface 124 of each respective yokebranch 122 of the humeral component 100. The exterior humeral interfacesurface 302 further defines a humeral interface stud 304 that extendsaway from the humeral interface surface. As shown in FIGS. 18 and 19,one embodiment of the bearing liner 300, the humeral interface stud 304defines an annular collar 306 and frustoconical cap 308. The annularstud collar 306, preferably as an outer diameter “D” greater than anouter diameter “D” of the humeral interface stud 304, such that theinterface stud may be inserted and removably retained within the bearingbore 130 of the yoke branch 122, as shown in FIG. 19. In variousembodiments, the humeral interface stud 304 is retained in the bearingbore 130 using a detachable press-fit or snap lock arrangement.Alternately, in other embodiments, the humeral interface stud 304 andbearing bore 130 may be formed with complimentary threads to provide athreaded engagement.

The humeral interface stud 304 also defines an interior void 312, asshown in FIGS. 18 and 20 that is dimensioned to receive the bearing ears220. The interior void surface 314 is composed of a polymer that permitsarticulation and rotation of the bearing ears 220 and therefore theulnar component 200 once positioned within the bearing liners 300, asshown in FIG. 28.

Along the outer annular surface 310 of each of the bearing liners 300 aposterior trap opening 316 is in communication with a trap channel 318.The posterior trap opening 316 is defined along the outer circumferenceof the bearing liners 300. The posterior trap channel 318 is incommunication with the opening 316 and disposed radially along aninterior surface of the bearing liners 300. As shown in FIG. 7, wheninitially disposed with in the yoke branches 122, the posterior trapopenings 316 of the liners 300 align with the trap shoulders 146 to forman aperture to receive the retention trap 400. Similarly, each posteriortrap channel 318 also provides a conduit for receiving and guiding theulnar bearing ears 220 into the desired position during assembly.

The outer annular surfaces 310 of the bearing liners 300 also include alocking flange 320. The locking flange 320 contacts the lock shoulder148 of the slot 144 to lock the liners 300 into place once the linersare inserted and rotated into the hemispherical recesses 126. Inparticular, the liners 300 are engaged to the yoke branch 122 byinserting the humeral interface stud 304 into the bearing bore 130 andthen rotating the liners into a locked position during assembly. Thisprevents the liners 300 and the ulnar component 200 from disassemblingor dislocating once the liners are locked in place.

The Retention Trap

The retention trap 400, as shown in FIGS. 9 and 21-25 is a removablecomponent that functions as a keystone to “lock” the ulnar component andthe articulation bearing liners 300 within the humeral component 100.The retention trap 400 includes humeral component interface surfaces402A-B, liner interface surfaces 404, and interior articulation surfaces406 and ulnar bearing ear interface surfaces 408. In one aspect, theretention trap 400 is composed of a polymer, including but not limitedto polyethylene.

By way of example and not limitation, in one embodiment, the humeralcomponent interface surfaces 402A-B are static interfaces relative tothe humeral component once fully assembled. In particular, humeralcomponent interface surfaces 402A contact the interior edges 142 of theyoke branches 122, while the humeral component interface surfaces 402Bcontact the interior surface 124 of each respective yoke branch 122. Inone aspect, the trap 400 is inserted through an opening defined by thetrap shoulders 146, where the liner interface surfaces 404 translatepast the trap shoulders. As such, once the retention trap 400 has beeninserted into the humeral socket 106, engages the liners 300. Duringrotation to lock the liners 300 inside the humeral socket 106, thehumeral component interface surfaces translate along the slot 144. Afterthe liners 300 are locked in place, the trap remains in a staticconfiguration, while the ulnar component 200 is able to articulatewithin the space bounded by the liners, the trap 400, and humeral socket106. In this aspect, the retention trap 400 does not rotate orarticulate with extension or flexion of the ulnar component.

The liner interface surfaces 404 of the trap also contact and engage theposterior trap channel 318 of the liner 300. As shown, the linerinterface surfaces 404 are adjacent to the ulnar bearing ear interfacesurfaces 408, as shown in FIG. 21. The ulnar bearing ear interfacesurfaces 408 contact an exterior portion of the ulnar bearing ears 220that are disposed with the stud interior void 312. As shown in FIGS. 21,22 and 24, the bearing ear interface surfaces 408 are generally concaveand have a radius of curvature substantially similar to that of theulnar bearing ears 220.

The interior articulation surfaces 406 are generally concave and contactthe ulnar component 200 which articulates against them during flexionand extension of the assembled prosthetic device 10. As shown in FIGS.2, 22 and 25, the interior articulation surfaces 406 may further definean extension channel 410 that permits full extension of the ulnarcomponent 200 when it is positioned within the humeral component. Duringassembly, the trap 400 and liners 300 are rotated relative to thehumeral component 100 until the liners “snap” into place. Once thisoccurs, the prosthetic device 10 is considered locked.

The retention trap 400 also includes a tool bore 412 that extends fromthe outer surface of the trap to the interior articulation surface 406,as shown in FIGS. 21-22 and 32-36. As explained, more fully below, thetool bore 412 is dimensioned to receive a tool (not shown) that extendsthrough the retention trap 400 and engages the ulnar component 200 in anulnar bore 230 shown in FIG. 14. A tool inserted through the tool bore412 provides leverage to rotate the trap 400 and liners 300 duringinstallation or removal of the device 10.

The present disclosure also relates to various methods for implanting,assembling, and using the elbow prosthetic device 10. FIG. 29 is a flowchart depicting one embodiment of a method 500 for implanting and usingany embodiment of the elbow prosthesis 10, as described above. At 502,an unassembled prosthetic device, such as the prosthetic device 10 isprovided. In one aspect, the unassembled device includes the humeralcomponent 100, the ulnar component 200, the bearing liners 300, and theretention trap 400. After proper patient preparation and sterilization,as understood by one having ordinary skill in the art, an incision ismade in a desired arm of patient at 504 to expose the implantation site.In one aspect, the condition of the patient's ulna and humerus areaccessed to determine the amount of hard and/or soft tissue that must beresected. The ulna and humerus may undergo additional preparation toprepare the bones for receiving the implants. This preparation includesany number of steps readily understood by one having ordinary skill inthe art. For example, in one aspect, a distal end of the humerus may beresected and additional bone fragments may be removed to expose thedistal end of the humerus.

After making the incision and, optionally, visually inspecting thepatient, the proper size for each of the components of the device 10 isdetermined at 506. This determination may be made using diagnosticimaging or other sizing determinations, including but not limited tovisual comparisons. In one aspect, a size determination for eachcomponent of the device 10 may include temporarily implanting varioussizes of the humeral component 100 and the ulnar component 200, whileassessing such factors as the soft tissue balance, the range of motion,joint spacing, and stability, among others.

At 508 and 510, the humeral component 100 is secured to the humerus ofthe patient and the ulnar component 200 is attached to the humeralcomponent, respectively. In one aspect, attaching the ulnar component200 to the humeral component 100 may also include rotatably coupling theulnar component to the humeral component. In another aspect, whenattaching the ulnar component to the humeral component 100, one or morebearing liner 300 is secured to the inner surface of the humeral socket106. In yet another aspect, the ulnar component 200 is rotated fromninety degrees of hyperextension with respect to the humeral component100 and rotating the ulnar component from extension into flexion duringassembly. As shown in FIGS. 30-31, one advantageous feature of the ulnarcomponent 200 is that the fully spherical bearing head 204 may beinserted into the humeral socket 206 in any of a number of orientations.

In one aspect, The ulnar component 200 is locked and retained within thehumeral component 100 using the bearing liners 300 in combination withthe retention trap 400. For example in this aspect, as shown in FIGS.32-36, the ulnar component 200, or at least the bearing head and neckportion thereof, is inserted into the humeral socket 106 after placementof the bearing liners 300. The retention trap is then inserted into theopening defined by the trap shoulders 146. The retention trap andbearing liners 300 are then rotated about the ulnar component 200 in aposterior direction, generally indicated as 600, away from the humeralflange 104. This rotation causes the resilient outer annular surfaces310 and the locking flange 320 in particular, to be compressed or flexedinwards towards the ulnar neck 206 as they contact and traverse thenarrowed region 149 of the slot 144. Once the locking flange 320 of eachliner 300 has traversed the narrowed region 149, the resilient annularsurfaces flex outward, where the locking flange engages the lock should148 to prevent retrograde rotation of the liners. Simultaneous with theliner 300 rotation, the retention trap 400 is also rotated such that thehumeral component interface surfaces 402A slide along the interior edges142 of the yoke branches 122, while the humeral component interfacesurfaces 402B contact and slide the interior surface 124.

As the retention trap 400 is fittingly engaged to the liners as shown inFIGS. 26-28, it is also prevented from retrograde rotation.Additionally, the humeral component interface surfaces 402B prevent theretention trap from translating in a posterior direction out of the slot144. Both the retention trap 400 and liners 300 are thereforeimmobilized within the humeral socket 106, which therefore prevents theunintentional removal of the ulnar bearing 204 from the humeral socket.FIGS. 32-35 illustrate an embodiment of the method 500, where a portionof the ulnar component 200 such as the ulnar bearing 204 and the ulnarneck 206 are be engaged and retained in the humeral socket 206 beforethe ulnar stem 202 is engaged to the neck. In other embodiments, theliners 300 and retention trap 400 may be rotated and/or locked after thestem 2002 is engaged to the ulnar neck 206.

At 512, the ulnar component 200 is secured to the ulna of the patient.In other embodiments, the ulnar component 200 is secured in the ulna ofthe patient prior to attaching the ulnar component to the humeralcomponent 100. In one alternate embodiment, after securing the ulnarcomponent 200 to the ulna, the ulnar component is then engaged to thehumeral component 100.

At 514, the incision in the patient is closed. According to otherembodiments, prior to closing the incision, a guiding system includingan insertion tool may be used for inserting at least one fixation deviceinto the stem of the ulnar component prior to implantation.Additionally, soft tissue structures proximal the elbow prosthesis 10may be balanced and attached to the prosthesis using sutures or othersuitable connecting components. Moreover, the functionality of theimplanted elbow prosthesis 10 may be assessed before closing theincision, after closing the incision, or both.

In various other embodiments, the order of the steps for affixing thedevice 10 to the patient the device may be varied; however to securelyengage the ulnar component 200 to the humeral component 100, the liners300 are positioned with humeral socket 106 prior to inserting thebearing head 204, regardless of orientation, as shown in FIG. 31.

The foregoing merely illustrates the principles of the disclosure.Various modifications and alterations to the described embodiments willbe apparent to those skilled in the art in view of the teachings herein.It will thus be appreciated that those skilled in the art will be ableto devise numerous systems, arrangements and methods which, although notexplicitly shown or described herein, embody the principles of thedisclosure and are thus within the spirit and scope of the presentdisclosure. From the above description and drawings, it will beunderstood by those of ordinary skill in the art that the particularembodiments shown and described are for purposes of illustrations onlyand are not intended to limit the scope of the present disclosure.References to details of particular embodiments are not intended tolimit the scope of the disclosure.

What is claimed is:
 1. An elbow prosthesis comprising: an ulnarcomponent including: a spherical bearing head comprising one or moreprojection ears extending away from the bearing head along a centraltransverse axis of the bearing head; the bearing head coupled to anulnar stem extending away from the bearing head in a direction generallyperpendicular to the transverse axis; a humeral component including: ayoke; a pair of opposing yoke branches extending from the yoke, whereinan interior surface of each yoke branch is concave and an exteriorsurface of each yoke branch is convex such that the interior surface ofthe yoke branches define a spherical socket therebetween to retain thespherical bearing head disposed therein, each of the opposing yokebranches further defining a slot having one or more trap shoulders and alock shoulder thereon; a stem extending from the yoke opposite the pairof opposing yoke branches; at least one resilient articulation liner,wherein the resilient articulation liner includes a flange engaged bythe lock shoulder, the resilient articulation liner thereby coupled tothe interior surface of at least one of the pair of yoke branches anddisposed within the spherical socket between the at least one yolkbranch and the spherical bearing head; and a retention trap for lockingthe ulnar component and the at least one articulation liner within thehumeral component, the retention trap received by the one or more trapshoulders and coupled to the at least one resilient articulation liner,the bearing head and the one or more projection ear, and wherein theretention trap is configured to rotate relative to the humeral componentto lock the ulnar component.
 2. The elbow prosthesis of claim 1, whereinthe yoke slot further comprises a throttled region defined by at leastone inwardly tapered portion of each yoke branch.
 3. The elbowprosthesis of claim 1, wherein the locking shoulder engages the at leastone articulation liner to prevent rotation of the at least onearticulation liner.
 4. The elbow prosthesis of claim 1, wherein the atleast one resilient articulation liner includes a resilient outerannular surface and a locking flange and the yoke slot further comprisesa throttled region defined by at least one inwardly tapered portion ofeach yoke branch and the at least one locking shoulder; wherein thethrottled region compresses the resilient outer annular surface and thelocking flange of the at least articulation liner during translation ofthe at least one articulation liner; and wherein the articulation linerreturns to an uncompressed configuration after the locking flange of theat least one articulation liner has traversed the throttled region andthe locking flange engages the at least one locking shoulder.
 5. Theelbow prosthesis of claim 4, wherein he retention trap is engaged to theat least one resilient articulation liner during translation of the atleast one resilient articulation liner.
 6. The elbow prosthesis of claim5, wherein the at least one articulation liner and the retention trapare immobilized in an assembled configuration and retain the ulnarcomponent with respect to the humeral component.